SLVSAA4G June   2010  – February 2018 TPS65251

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Schematic
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Adjustable Switching Frequency
      2. 8.3.2  Synchronization
      3. 8.3.3  Out-of-Phase Operation
      4. 8.3.4  Delayed Start-Up
      5. 8.3.5  Soft-Start Time
      6. 8.3.6  Adjusting the Output Voltage
      7. 8.3.7  Input Capacitor
      8. 8.3.8  Bootstrap Capacitor
      9. 8.3.9  Error Amplifier
      10. 8.3.10 Loop Compensation
      11. 8.3.11 Slope Compensation
      12. 8.3.12 Powergood
      13. 8.3.13 Current Limit Protection
      14. 8.3.14 Overvoltage Transient Protection
      15. 8.3.15 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Low-Power Mode Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1  Loop Compensation Circuit
        2. 9.2.2.2  Selecting the Switching Frequency
        3. 9.2.2.3  Output Inductor Selection
        4. 9.2.2.4  Output Capacitor
        5. 9.2.2.5  Input Capacitor
        6. 9.2.2.6  Soft-Start Capacitor
        7. 9.2.2.7  Bootstrap Capacitor Selection
        8. 9.2.2.8  Adjustable Current Limiting Resistor Selection
        9. 9.2.2.9  Output Voltage and Feedback Resistors Selection
        10. 9.2.2.10 Compensation
        11. 9.2.2.11 3.3-V and 6.5-V LDO Regulators
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Power Dissipation
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.2.8 Adjustable Current Limiting Resistor Selection

The converter uses the voltage drop on the high-side MOSFET to measure the inductor current. The over current protection threshold can be optimized by changing the trip resistor. Figure 17 governs the threshold of over current protection for Buck 1. When selecting a resistor, do not exceed the graph limits. In this example, the over current threshold is 3.2 A. In order to prevent a premature limit trip, the minimum line is used and the resistor is 100 kΩ.

When setting high-side current limit to large current values, ensure that the additional load immediately prior to an overcurrent condition will not cause the switching node voltage to exceed 20 V. Additionally, ensure during worst case operation, with all bucks loaded immediately prior to current limit, the maximum virtual junction temperature of the device does not exceed 125°C.